TRAVELING IN STYLE : BIZARRE BAZAAR : It is wisely said that anything stolen during the week is bound to reappear on Sunday--before 100,000 people--at Rome’s flea market

There is no known antidote for what happens to tourists at Rome’s haggle-happy flea market. Some call it “the disease” because it brings on an acute case of the buying fever. At this Sunday morning outdoor bazaar, you can buy anything and everything. It is one of the world’s largest open air marts, extending for three quarters of a mile along the banks of the Tiber.

In Rome, it is wisely said that anything stolen during the week is bound to turn up Sunday in the ocean of bric-a-brac that never attracts fewer than 100,000--tourists, local citizenry and whatever celebrities are in town.

The walls that surround the flea market were built by Pope Urban VII nearly 400 years ago, and the gateway that leads into the oversized jumbo sale bears the insignia of Innocent X (1644-1655). The enormous repository itself, however, was already hoary with age when these pontiffs reigned. No one knows when the market started, but it goes back to the era when the Tiber River served as the port of Rome and Roman sailors did a bit of illicit trading on the side.

You’re never quite prepared for the avalanche of junk that bombards your eyes at this bargain mecca, which opens at sunrise--when the air in Rome is gentle. It continues at a furious pace until 1 p.m., when the 800-or-so hucksters pack up their wares. Spread out on tables, counters, stalls, boxes, wagons, blankets, carpets and newspaper sheets are uncountable thousands of worn out, shabby, broken, rust-cankered, faded, moldy, weather-beaten items of merchandise.

At the Mercato di Porta Portese, which is its official name, you are likely to spot such unlikely items as the shell of a turtle, war medals by the ton, parts of banisters, butcher scales, a plate of glass eyes, police billies, books about Mussolini, bolo knives, perfume atomizers . . .

And a Hawaiian war shield, wooden shoes, a Roman cat-o’nine-tails, live canaries, a Russian fur cap, more books about Mussolini, rusty chains (hopelessly knotted), bound copies of Corriere della Sera, a collection of wax papooses, wine presses, marble busts (with noses invariably broken off), rusty rifles . . .

And heaps of squashed straw hats, World War I gas masks, false teeth, puppies, Wagner’s score of “Lohengrin” (with Page 42 missing), old carabinieri riding boots, Oriental carpets, even more books about Mussolini, a copper birdbath with marble stand, cracked Victrola records with vocals by Rudy Vallee.

And etchings, the key to the city of Dallas, Etruscan objects (counterfeit), door-knockers, English shoes with built-in spats, thermos bottles, patched inner tubes, fur coats, a vintage Singer sewing machine and a great number of other objects.

Occasionally, visitors who know what they are buying will come up with a good purchase. Several years ago, Sidney Simon, an American artist, picked up a 15th Century painting for $16. Poet John Ciardi found four “lovely 19th Century heads from some ripped paintings” for $20. The curator of an art institute got a bargain for $8 when he took home an oil from the early 1800s. And not long ago, it was learned that the Norwegian painter Alf Lundeby bought, for the equivalent of less than $2, a 10x7-inch copper-plate picture of St. Hieronymus that turned out to be a genuine Raphael.

But art discoveries of that type are few and far between.

No, there is not much chance that an alert traveler will ever pick up a Monet, a Corot, A Cezanne watercolor or even a lost Modigliani. But that doesn’t mean people will stop trying to buy paintings at steal prices. That’s part of the fun at the Roman mercato.

The method of buying anything follows a standard procedure. A tourist quickly learns that there is, first, the price that sharpie shopkeepers ask and second, the price they will sell for. To purchase anything, you must engage in a seesaw contest, that is invariably synchronized with facial movements, shoulder undulations, hand motions, melodramatic protestations and other appeals.

Somewhere in the middle of this Sunday madness, a strongman sidewalk sideshow will be going on. Bare-chested, the leviathan breaks chanins with histrionic inhalations of heavy breathing while his long-haired female partner wanders around collecting coins and bumming cigarettes. Though the muscle man could easily have stepped out of “La Strada,” it is evident, nonetheless, that this is a flea market not a film set.